Prognostic value of the systemic immune-inflammation index in acute non-variceal upper gastrointestinal bleeding: a retrospective single-center cohort study.

backgroundAcute non-variceal upper gastrointestinal bleeding (NVUGIB) is a life-threatening emergency associated with significant morbidity and mortality. Current risk stratification tools have limitations in predicting short-term outcomes. The Systemic Immune-Inflammation Index (SII), a composite biomarker integrating platelet, neutrophil, and lymphocyte counts, has shown prognostic value across various acute conditions; however, its utility in NVUGIB remains unexplored.

methodsIn this retrospective single-center cohort study, 812 adults presenting with NVUGIB to the emergency department of Kartal Dr. Lütfi Kırdar City Hospital (Istanbul, Turkey) were analyzed. SII was calculated as (platelet count × neutrophil count) / lymphocyte count. Primary outcome was 28-day all-cause mortality; secondary outcome was 72-hour rebleeding. Discriminative performance was assessed using receiver operating characteristic (ROC) curve analysis and compared with established risk scores (Glasgow-Blatchford Score, pre-endoscopic Rockall Score, complete Rockall Score, and AIMS65). Independent predictors were identified using multivariable logistic regression and Cox proportional hazards analyses.

resultsThe 28-day mortality rate was 6.5% (n = 53) and the 72-hour rebleeding rate was 11.1% (n = 90). Median SII was significantly higher in non-survivors compared to survivors [1,714.9 (IQR: 980.5-3,776.0) vs. 910.5 (IQR: 599.3-1,501.0); p < 0.001]. For 28-day mortality, SII achieved an AUC of 0.704 (95% CI: 0.622-0.785), comparable to established scoring systems (all p > 0.05 by DeLong test). Notably, SII demonstrated superior discriminative performance for 72-hour rebleeding (AUC = 0.767; 95% CI: 0.714-0.820), significantly outperforming GBS (AUC = 0.540), AIMS65 (AUC = 0.541), pre-endoscopic Rockall Score (AUC = 0.561), and complete Rockall Score (AUC = 0.554). In multivariable logistic regression, SII (per 100 units; OR = 1.02, 95% CI: 1.02-1.03; p < 0.001) was an independent predictor of mortality. Decision curve analysis demonstrated that adding SII to existing scores improved net clinical benefit.

conclusionsSII is an independent prognostic marker in NVUGIB, offering discriminative performance for 28-day mortality comparable to established risk scores and superior performance for 72-hour rebleeding prediction. As a simple, routinely available laboratory index, SII may complement existing risk stratification tools in the emergency management of NVUGIB.